Khusimone has been recognized as being mainly responsible for the characteristic scent of vetiver oil [Vetiveria zizanioides (L.) Nash], an important natural raw material currently used for compounding fine fragrance compositions [see e.g. Swiss Pat. No. 576,238, wherein its preparation, starting from natural occuring zizanoic acid, has been described]. Two total syntheses of starting zizanoic acid have been published in the scientific literature [see: Tetrahedron 27, 1481 (1971); Chem. Comm., 1335 (1969) and J. Chem. Soc. Perkin I, 1775 (1972)] , however their interest is exclusively academic as they can not be industrially practicable.
By the process of the invention it is possible to prepare racemic khusimone starting from 6,6,7-trimethyl-tricyclo[5.2.2.0.sup.1,5 ]undec-8-en-2-one, which compound can be obtained from easily available synthetic starting materials.